The Intraoral Fluoride Releasing System (IFRS) is being developed by the NIDR in order to investigate the efficacy of continual topical fluoride for the prevention of dental caries. The IFRS consists of a small controlled-release delivery system for fluoride, the Intraoral Fluoride Releasing Device (IFRD), and the method for retaining and protecting the IFRD in the mouth. The IFRS is designed to be attached to a molar tooth and to provide continual topical fluoride for six months without maintenance or adjustment. Clinical studies in adolescents recently completed by contractors at the Eastman Dental Center demonstrated that an appropriately designed IFRS can maintain significantly elevated concentrations of fluoride in saliva for at least six months without producing adverse effects and with excellent patient acceptance. These results, combined with earlier animal trials which demonstrated the efficacy of the IFRD in preventing experimental dental caries, suggest that the IFRS could be useful for controlling dental caries, especially in high-risk individuals. A clinical protocol is presently being developed for evaluating the efficacy of the IFRS for the prevention of dental caries in children.